Booby-trapping bacteria

Shrinkage: Research updates on the quest to make really tiny things

MIT bioengineer Alexander Klibanov is devising a nasty weapon to ward off microbes: a bed of nanoscopic nails. Affixed to computer keyboards, countertops and fabrics, the nails would puncture germs the way road spikes pierce tires, providing permanent protection against bacteria, Klibanov says.

The antibacterial agents found in soaps and aerosols work like poisons. Chemicals leach into the bacteria and disrupt a vital function, such as sugar digestion. Trouble is, the chemicals tend to wear off quickly, requiring repeated usage and giving hardier mutant bacteria an opportunity to flourish. Klibanov´s nails–each about a millionth the width of a human hair–kill with brute force, rupturing multiple structures. And they won´t wash away.

Or hurt you. The â€nails†are actually long, pointy chains of carbon atoms that are big enough to lance bacteria but too small to harm
larger, mammalian cells. Each chain carries a positive charge that attracts and ruptures negatively charged bacteria.

In a study published in June, glass treated with the spikes wiped out 96 percent of 11 generations of Staphylococcus aureus, a common cause of skin infection. Klibanov hopes to have his germ lancers ready for action by 2008.